Comment by hunterpayne

Sure, if you ignore all the parts of the neutron economy that make it possible to work. The part everyone missed in this discussion is that all of the numbers of neutrons (and their barns) aren't constants. Since the fuel is a fluid, you can use density and shape to improve the neutron economy in the reactor core. Basically, when the atoms are closer together, the economy improves. You can also use a better moderator like graphite since the basic design is safer and the rate of fission is just easier to control.

And considering that people made these things work 60 years ago without modern computers, the idea that its impossible or needs 40 years of research seems pretty far fetched. What is left of the nuclear industry wants to build current designs like the AP1400. That is a great idea, but there are things you can do with a LFTR that you can't do with an AP1400. The biggest of them is making synthetic fuel. The other advantages are the amount of waste produced and the fact that you can make a LFTR into a waste burner consuming the spent fuel rods from a AP1400. The downside is you actually have to fix nuclear regulations to do this and getting politicians to do that has proved impossible.

There are no technological barriers, this is entirely political.